Chiropractic is a system of treating disease by manipulation of the vertebral column, and is based on the premise that pain can be caused by pressure on the nerves because of faulty alignment of the bones, which prevents the nerves from transmitting to various parts of the body the neural impulses for proper functioning.
The muscles of the human body are substantially symmetric on the right and left sides of the body. This fact has led to research on the effect of unequal strength in similar muscles on right and left sides of the body. Some research has shown that such unequal strength increases the risk of injury in athletes.
Also, in chiropractic, such unequal right and left strength is thought to be an indicator of nerve interference. When it is found that a muscle or muscle group on one side is stronger than the same muscle or muscle group on the opposite side, chiropractors can treat the nerve controlling the weak muscles by manipulation and other techniques to remove pressure on the nerves or like interference which inhibits the activity of the nerves, and leads to weakness in the muscles. Successful treatment can be determined when muscle strength on each side is substantially equal.
The difference in muscle strength in the same muscles on right and left sides need not be great, and a difference of 5% can be significant. Conventional techniques and equipment have not conveniently and economically allowed for accurate determination of differential muscle strength. It is known to use hand held devices to measure strength. In one technique, the treating person pushes an air bag against the patient's arm, leg, head, or like body part and the patient's muscle resistance is measured by noting the pressure in the air bag.
Biodex Medical Systems of Shirley, N.Y., USA also makes a machine which can very accurately measure kinetic and isometric muscle strength. Most of the tests are done while the person being tested is seated. Cybex International of Medway, Mass., USA also makes machines for muscle strength testing. Such machines are however quite costly and occupy considerable space, making them impractical for wide usage.
An economical and accurate apparatus for measuring the strength in similar muscles on right and left sides of the body would allow for regular testing of, for example, athletes, industrial workers with a high potential to develop muscular skeletal problems, or who are known to have such problems, to detect such inequalities early and treat same to avoid injuries. Patients of medical professionals such as chiropractors, physiotherapists, doctors, sports trainers, and the like would benefit from the ready ability to measure right and left side muscle strength.